Sinaptec DIY build

This is Sinaptec 3d printer controller board i have build while ago. It runs on Arduino Nano V3 with Teacup Firmware and i have on major issue which i cannot solve by myself. Controller cannot heat up hotend, after sending gcode. PC shutdown (i suspect it takes too much 5V current from USB )

So far works: pc connection, motors, thermistors, endstops
[streamable.com]

What worries me the most is the second pic. those two LEDs on right should not be lit/glow

Tested MOSFETs with multimeter in diode test mode and there is no connection between drain and source.
Voltage regulator on left side takes 12.6V DC and output is stable 4.98V DC

And i am out of ideas how to solve this, especially when my know-how in electronics is basic at most. Any help or input will be appreciated.

Can you link to any schematics? A pic from the back of the PCB would also be helpful.
Switching MOSFets on/off, should not overload the 5V regulator. It seems, you are making a shortcut by switching the FET, but where?
What about the extruder-heater? Does it work?

How do you use the driver ports? The capacitors are too tall..

[reprap.org]

I can't get decent photo from back of PCB that doesn't glow or is out of focus.
But already checked for bad soldering or any shorts.
Probed resistors, diode even LEDs, all in spec.

This board is prototype, yeah i know that soldering them at bottom would be better way to do it. As for how i use it, stepstick have "extension" as seen on streamable vid.
Later i would just replace caps and mount them at bottom.

But this board will be scrapped. Now controller shutdown PC when i plug USB while powered from 12V.